Description of Prior Art
There have been offered various kinds of exposing apparatuses to expose a work with a predetermined pattern by ultraviolet rays. These conventional exposing appratuses expose a work by irradiation of ultraviolet rays after confirming a proper locational relation of a work and a mask film with each other by a camera when the work is held by printing frames. A CCD (charge coupled device) type image receiver is utilized for the camera.
An alignment working of the work and the mask film is carried out in an exposing section and this alignment working is called an inside locating system. In such a locating system alignment and exposing working are carried out in a straight line and thus productivity of exposed works is not as improved as expected.
In order to overcome the aforementioned defects the applicant already filed a Japanese laid-open Patent application with publication number of 4-350857. The application of 4-350857 comprises alignment and exposing workings in which the alignment and exposing workings are carried out outside an exposing section. This system is called an outside locating system. In the application of 4-350857 the outside locating system is utilized its advantages and high alignment accuracy of the work and mask film is performed.
As shown in FIG. 26, an exposing apparatus 100 comprises a feed-in stage 101, an alignment stage 102, an upstream unit 105 comprising an exposing stage 103 and a discharge stage 104, a reverse stage 106 of a work W located rearward of the discharge stage 104 of the upstream unit 105 and a downstream unit 111 being located rearward of the reverse stage 106 and comprising a feed-in stage 107, an alignment stage 108, all exposing stage 109 and a discharge stage 110.
A traverser 112 of the upstream unit 105 to transfer works to each stage is provided with a printing frame 113 located in the center thereof and handlers 114 and 115 located at both sides of the printing frame 113. On the other hand, a discharge device 120 of the downstream unit 111 is provided with a printing frame 121 located in the center thereof and handlers 122 and 123 located at both sides of the printing frame 121.
There are provided with delivery tables 117 and 125 movable holding another printing frames 116 and 124 between the alignment stages 102 and 108 and the exposing stages 103 and 109, respectively.
The reverse stage 106 is provided with a reverse unit (not shown) to reverse the work W from upper surface to under surface. The work W reversed at the reverse stage is supplied to the feed-in stage 107 of the downstream 111 by means of a handler (not shown).
Further, as shown in FIG. 28, the upper printing frame 113 (121) is provided with a vacuum suction mechanism 130 to suck the work with the lower printing frame 116 (124). The vacuum suction mechanism 130 comprises suction supporting sections 133a-133d mounted in the four corners of a transparent plate 131, a sealing rubber 134 of frame like pattern fitted to the work contacting to the transparent plate 131 and suction hoses 135 supported by the suction supporting sections 133a-133d. The transparent plate 131 is held by an openable frame 132 for vacuum suction. The transparent plate 131 is provided with through holes (not shown) at each location of the supporting sections 133a-133b.
Further, as shown in FIG. 27, the lower printing frame 116 (124) comprises a transparent plate 116b provided with a plural number of through holes 116a, a frame body 116c supporting the transparent plate 116b and a fitting section 116d for a suction hose 116e provided in the frame body 116c. Each row of the through holes 116a of the transparent plate 116b is communicated with each row of vacuum grooves 116f.
The work is transferred to the reverse stage by means of transferring means (not shown) to reverse said work from upper surface to under surface. The reversing mechanism applied in this reverse action is such one as disclosed in Japanese laid-open application published with publication number of 4-46445. The reverse unit comprises a delivery table to receive the work and to transfer the work to a predetermined position and a suction reverse unit to suck the work from the delivery table.
In the upstream unit 105 and the downstream unit 111 there are provided with control devices and ultraviolet rays irradiation devices, respectively. The ultraviolet rays irradiation device applies an ultraviolet lamp of 5 KW or thereabout. In conventional exposing apparatus, the ultraviolet lamp is not relighted. It is, therefore, always lighted during the operation and used for shutter mechanism of cameras, or the like. If ultraviolet rays is not required during operation the shutter mechanism is closed to cut the ultraviolet rays.
The order of processes of the exposing apparatus 110 including delivery, alignment, exposure and reverse of the works is as follows:
The work W is transferred to the alignment stage 102 by means of the handler 115 of the traverser 112 from the feed-in stage 101 of the upstream unit 105. The work held by the upper printing frame 113 and the lower printing frame 116 is aligned on the alignment stage 102. The upper printing frame 113 of the traverser 112 sucks the aligned work and the lower printing frame 116 to transfer them to the exposing stage 103. The work W exposed its one surface is transferred to the discharge stage 104 by the handler 114 of the traverser 112 and reversed its surface from upper surface to under surface at the reverse stage 106. Then it is transferred by a traverser (not shown) to the downstream unit. The operarion carried out in the upstream unit 105 is repeated in the downstream unit 105 and the other surface of the work W is exposed. The exposed work is then discharged.
According to the aforementioned processes an accurate alignment effect is obtained and productivity is improved.
However, there still remain some defects to be improved as follows:
(1) In the aforementioned exposing apparatus, the structure of traverser, direction of transfer, location of devices are all arranged in straight line, thus the size of the cleaning room to proceed exposing operation occupies large space. PA1 (2) The exposing apparatus provides ultraviolet rays irradiation devices in its upstream and downstream units, respectively. Each of the upstream and downstream units is provided with control device, thus the size of the whole system becomes larger and consumption of electric power becomes larger. PA1 (3) When transparent plate becomes deteriorated after long time use it is necessary to replace the transparent plate provided with mask or mask transparent plate. The upper printing frame is provided with a suction mechanism such as a suction hose to suck the work and suction pads, or the like. It causes troublesome to replace the suction mechanism. It is also required to stop whole processes of exposing working for several hours to replace the transparent plate. PA1 (4) When vacuum suction by the lower printing frame to transfer the work is too tight between the work and the lower printing frame of the transparent plate, it is not possible to take off the work from the transparent plate and then operation is obliged to stop. The lower printing frame is provided with the suction hose and a plural number of the upper and lower printing frames to serve as vacuum frame are required. The structure which corresponds to such a new tendency is required. PA1 (5) The work is held by the lower printing frame or held between the upper and lower printing frames to be transferred and exposed. It is required to transfer the work so that positional deviation amount of said work on the lower printing frame may become as small as possible. PA1 (6) In arrangement of the reverse stage to reverse the work from upper surface to under surface it is required to provide a discharge stage in the upstream unit, reverse stage, and a feed-in stage in the downstream unit. This causes to prepare a larger working space. PA1 (7) In order to proceed alignment and exposing works, the vacuum frame retaining the work is held between the upper printing frame and the lower printing frame. As the handler and the upper printing frame are integrally formed, the whole structure becomes larger and controlling the apparatus becomes troublesome. Maintenance work is also troublesome. The lower printing frame and the upper printing frame are not removed each other so they are not possible to be treated independently. Thus working efficiency is not improved. PA1 (8) It is required to improve location of alignment of the vacuum frame and location of exposing the work so that more efficient exposing operation may be obtained. PA1 (9) When the work placed on the lower printing frame is transferred to each stage the work is sometimes displaced with positional deviation from the predetermined location. It is desired to prepare more accurate aligning device in the subsequent stages.